Completed the integration of vertexAI

Screencast from 24-12-24 03:01:59 PM IST.webm

Integration test

Unit test

• Implementation of Bedrock provider
• Unit tests with good coverage
• Integration tests with actual API calls (using test credentials)
• Documentation updates
• Example configuration
• Successful chat completion, completion, and embedding requests
• Error handling and proper status code mapping
• PR review and approval

fix #19 /claim #19